My grandfather's older sister passed away at 89. She lived about 100 km away from us. My grandfather…

My grandfather's older sister passed away at 89. She lived about 100 km away from us. My grandfather is 84 and said he can't go because he's not feeling well and wouldn't be able to handle it. My mom can't go either, her leg hurts and she's limping. However, my grandfather asked if I could go and take a wreath. I agreed. They're burying her on Monday, and my husband and I will drive there. The problem is, I don't remember anyone, and I don't recognize faces. They only spoke on the phone, and I last saw her 13 years ago at my grandmother's funeral. Honestly, I don't know who to approach or what to say. I was planning to just go to the cemetery, place the wreath, and throw a handful of dirt. Is that enough? Or should I attend the funeral service? I've never been to anything like this before.